1. Field
Embodiments of the present invention relate to a vehicle control apparatus and a vehicle control method.
2. Description of the Related Art
An Anti-lock Brake System (ABS) of a vehicle serves to prevent locking of a wheel by appropriately adjusting a braking pressure applied to the wheel based on a slip rate that is calculated from a wheel speed. A Traction Control System (TCS) serves to control drive power of an engine in order to prevent sudden unwanted acceleration or excessive slip upon sudden acceleration of a vehicle.
The ABS and the TCS may provide good performance when a vehicle travels on a straight road. However, when the vehicle turns, understeer (plow-out: the vehicle does not turn enough) or oversteer (spin-out: the vehicle turns more sharply than intended) may occur.
For this reason, there is a demand for a vehicle stability system to stably control the attitude of a vehicle, i.e. to prevent loss of vehicle steering under any traveling situation. In one example, if understeer occurs when the vehicle turns less than the amount commanded by a driver and leaves a desired traveling track outward, it may be necessary to apply brake force to a rear inner wheel, so as to prevent the vehicle from turning along a path with a radius larger than intended. If oversteer occurs when the vehicle turns more than the amount commanded by the driver and leaves the desired traveling track inward, it may be necessary to apply brake force to a front outer wheel.
Performance of the system to control vehicle stability when the vehicle turns is determined whether the system may accurately predict a vehicle turn-speed that will be commanded by the driver and apply appropriate braking pressure to front and rear wheels to allow the vehicle to turn based on the predicted turn-speed.
Further, it may be necessary to control vehicle stability without deterioration in the performance of the above-described ABS and TCS and to prevent the ABS and TCS from having a negative effect on vehicle stability. Therefore, to appropriately control vehicle stability based on vehicle motion, cooperative control between the vehicle stability system and the ABS and TCS may be important.